Solar water heating collectors have been used for domestic water heating for decades as they provide considerable savings in energy bills. Conventional flat-plate water heating collectors can provide high solar to thermal energy conversion efficiency and can fulfill many of the water heating demands of a building when storage of about one day's water use is provided. However the capital cost of installing water heating collectors remains an obstacle in its widespread use.
Transpired collectors actively pull air through small perforations in the absorber plate which leads to the heating of the air. The air movement suppresses convection losses as the heat conducted to the thermal boundary layer is continuously pulled back toward the plate. A transpired solar collector can perform efficiently at high suction velocities. However for lower suction velocities, required to achieve high air temperature desired for desiccant regeneration applications, the collector efficiency drops considerably.